The Research Of Deficient Irrigation Effect To Growth And Development And Production And Quality Of Tobacco

Water is one of the two ecology factors of tobacco growth and formation of tobacco yield and quality, and also the main mean to control tobacco yield and quality effectively. Tobacco will be sensitive to drought when the water deficiency excesses a certain degree, although it is able to fight drought strongly. When soil water appears to coerce, the physiological characteristics of tobacco will be changed. The pore circulation degree dimishes and partly closes, which influences the exchange of vapour and carbon dioxide ,then photosynthesis rate and transevaporation rate will fall down. As the result, the temperature of top layer and cell liquid density rises, the water coercing index of tobacco aguments.The results of lysimeter experiment and pot experiment illustrate that deficit irrigation can be carried at different growth periods without much influence to yield and quality of tobacco .The optimization low water limits of tobacco at the root-extended period, flourishing-growth period and maturing period are 60, 80, 70 percent of field water-holding rate respectively.Root-extended period is the key period of root growing, moderate deficit irrigation can boost the depth of root;flourishing-growth period is the main period of yield, moderate deficit irrigation can control tobacco growth ,avoiding excess growth ,which will influence tobacco quality;maturing period is the key period of tobacco maturing, excess water will delay maturing period and influence getting in tobacco .Therefore, moderate deficient irrigation should be carried either taking yield and quality of tobacco or water saving into account.